Electric brake.



PATENTED MAY 10, 1904.

- W. LASAR.

ELECTRIC BRAKE.

APPLICATION FILED FEB. 10, 1902.

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No.-759,288. PATENTED MAY 10, 1904. W. LASAR.

ELECTRIC BRAKE.

v APPLIUATION FILED FEB. 10, 1902.

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w. LASAR.

ELECTRIC BRAKE.

APPLICATION FILED FEB. 10, 1902.

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No. 759,288. v 'PATENTED MAY 10, 1904.

W. LASAR.

ELECTRIC? BRAKE. v APPLIOATION FILED FEB. 10, 1902. no MODEL. 4 SHEETS-SHEET 4,

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UNITED STATES WALTER LASAR, OF ST. LOUIS, MISSOURI, ASSIGNOR OF ONE-HALF TO Patented May 10,1904.

PATENT OFFICE.

LASAR ELEVATOR COMPANY, A CORPORATION OF MISSOURI.

ELECTRIC BRAKE.

SPECIFICATION forming part of Letters Patent No. 759,288, dated May 10, 1904.

Application filed February 10, 1902. Serial No. 93,471. (No model.)

in Electric Brakes, of which the following is a specification.

My invention relates to electric brakes, and has for its principal object to arrange the braking mechanism and the circuitcontrolling mechanism so as to be mutually interdependentv in their operation.

It consists in the arrangement and combination of parts hereinafter described and claimed.

In the accompanying drawings,which form part of this specification and wherein like symbols refer to like parts wherever they occur, Figure 1 is a side elevation of a hoisting mechanism provided with my invention. Fig. 2 is an end view thereof, and Fig. 3 is a diagrammatic View of the circuits. Fig. 4 is an enlarged vertical sectional view showing the connections to the tiller-rope and the automatic stopping device.

The main shaft 1 of the driving-motor 2 has a brake-drum or friction-drum 3 fixed thereon. Pivotally mounted in a suitable frame are a pair of brake-jaws 4, each consisting of a lever whose surface is curved to conform to the curve of the brake-drum 3. The ends of the brake jaws 4 are connected to opposite ends of a lever or double crank arm 5 by means of links or connecting-rods 6, whereby the movement of said lever 5 causes both brake-jaws to move simultaneously toward or away from the brake drum, as the case may be.

The lover or double-crank arm 5 is operated by a lever 7, fixed to the shaft thereof. A helical tension-spring 8 is connected at one end to the framework and at the other end to said lever 7, whereby it tends to retract said lever to its normal position. In order to adjust the tension of said spring, the end thereof is screw-threaded or provided with a screwthreaded hook or eyebar, and the lever 7 is provided with a threaded lug 9 to cooperate therewith.

The adjustment is maintained by means of set-nuts provided for the purpose. By this arrangement the spring always tends to set the brake. The lever 7 is connected by a link 10 at its end to the core 11 of a solenoid 12. Said lever 7 is also connected, preferably near its middle portion, by a link 13 to a circuit-closing lever or arm 14, arranged to open and close the connection to the powerwire.

In the operation of electric elevators it is desirable to provide means for reversing the motor, and for this purpose I provide a retary reversing switch 16, which is so arranged as not to interfere with the operation of the solenoid 12. A convenient device for operating the reversing-switch 16 is illustrated in the drawings. Loosely journaled on the projecting end of the shaft 17 of the winding-drum 17 is a yoke 18. This projecting end is screw-threaded and has a nut 19 Working thereon, said nut being provided with wings 20 or lugs which interlock with the yoke, whereby so long as the yoke is stationary the turning of the drum-shaft 17 causes the nut to have a motion of translation lengthwise of said shaft. At each end of the screw-threaded portion of the shaft is a fixed shoulder 21. WVhen the nut strikes against either shoulder 21, its motion of translation is stopped and the yoke 18 is forced to turn on its axis. The yoke 18 has a gearwheel 22 fixed thereto to revolve therewith, and this gear-wheel meshes with a segmental gear 23, journaled in the framework and having a crank-arm 24:, to which is pivotally connected a bar 25. This bar 25 is supported at its outer end and is provided with teeth to constitute a rack 26, arranged to intermesh with the teeth of a gear-wheel 27, fixed on the shaft of the reversing-switch 16. The shaft of the segmental gear 23 has a drum or pulley 28 fixed thereto and adapted to be manipulated by a tiller-cable 28. By this arrangement the motion of the tiller-cable is communicated through said pulley 28 and segmental gear 23 to the gear 22 on the yoke 18, and thereby moves said yoke. At the same time the movement of the tiller-cable is transmitted through the rack 26 to the reversing-switch 16. the required number of revolutions, the nut 19 jams the shoulder 21 and causes the yoke to be turned to its former position, whereupon the motion of the yoke 18 is transmitted,

. as above described, to the reversing-switch to effect the operation thereof and of the brake.

The arrangement of the circuits is illustrated in diagram in Fig. 3. As shown in this view, the line-wire 29 is connected to one winding 30 of the solenoid, and thence through one of the field-windings 31 of the drivingmotor 2, and thence to the contact-plate 32 of the circuit-breaking arm 14, where the circuit is normally open. This contact-plate 32 is arranged to contact with a brush 33 on the circuit-closing arm 14 and through said brush to a contact -plate 34. From this contactplate 34 the circuit to the other line-wire is completed in two multiple arcs or branches. One branch extends from the contact-plate 34 through the wire 35 to the second field-winding 36 of the motor 2 and thence through the wire 37, connected to the line-wire 38, and thereby completes the circuit through the dynamo at the power-station and the field-magnets of the motor. The second branch circuit extends from said contact-plate 34 through the motor-armature 39, as follows: from the contact-plate 34 to the rheostat 40 and thence through the Wire 41 to a contact-plate 42 on the reversing-switch and from this contactplate 42 to the wire 43, which wire is directly connected to the armature 39 of the motor, and through said armature and a Wire 44 connected thereto to a second contact-plate 45 on the reversing-switch and from said contact-plate 45 to the wire 46 and thence to the line wire 38, thus completing the circuit through the armature. Another circuit containing the second winding of the solenoid is completed as follows: from the line-wire 29, through a branch wire 29, to a contact-plate 47 or 47" on the reversing-switch 16 and thence to a wire 47, connected to one or the other of such plates, according to the position of the reversing-switch. From this plate 47 or 47 b the circuit continues through the second winding 48 of the solenoid and thence by means of a wire 49 to a contact-plate 50, which is arranged to contact at all times with a brush 51 on the circuit-breaking arm 14, and through the brush on said arm to a contact 52 and thence by a wire 53 to the plate 45 on the re versing-switch, which plate 45, as above described, is connected through the wire 46 to the line-wire 38. A circuit is thus completed through the second winding of the solenoid. As the pull of a solenoid increases as its core is drawn inwardly, this operation is counteracted by inserting a rheostat or resistancecoil 54 in the solenoid-circuit, said rheostat being in position to cooperate with the brush 51 on the circuit-breaking arm and throw in an increasing resistance as the circuit-break- WVhen the winding mechanism has made 7 ing arm progresses away from its normal position. Tapering the end of the core would cause the pull of the solenoid to be nearly uniform throughout.

It is noted that the wire 46 is permanently connected to one end of the line-wires and that the wire 41 is connected, as above described, to the other line-wire. The wires 43 and 44 constitute the switch-terminals of the armature branch, and the wires 47 and 53 constitute the switch-terminals of the solenoid branch in the normal position of the reversing-switch, in which position the circuits are all normally open. The three branch circuits are completed through the reversing switch by means 42, 45, and 47 as hereinbefore described, when the reversing-switch is turned into proper position.

In addition to the contact-plates 42, 45, and 47 the cylinder of the reversing-switch has sunk therein six more contact-plates, 47, 43, 41, 46, 44, and 53, in longitudinal alinement and arranged to contact, respectively, with the six terminal wires 47, 43, 41, 46, 44, and 53. The several contact-pieces are electrically connected as follows: The contactpiece 47 and the contact-piece 47 are insulated, and the contact-piece 53 is electrically connected to the contact-piece 46, whereby the shifting of the switch opens and closes the circuit of the second winding of the solenoid without changing the polarity. The contactpiece 43 is connected to the contact-piece 46, and the contact-piece 44 is connected to the contact-piece 41, whereby the terminal wires of the armature-circuit have their connections reversed, and consequently the current through said armature is reversed, according as the reversing-switch is turned in one direction or the other.

The operation of the device is as follows: The jaws of the brake are normally set against the brake-drum, so as to prevent the operation ofthe motor, the parts being in the position shown in Fig. 1 with the circuits broken at the circuit-breaking arm 14. To start the motor, the tiller-cable is pulled to shift the reversing-switch 16 and at the same time to set the yoke-nut at the proper point to stop the mechanism, as desired. This shifting of the reversing-switch 16 brings its contactplates into electrical contact with the circuitterminals to close the proper circuits of the motor as well as of the solenoid. The solenoid-circuit, which is normally open at the reversing-switch, is thus closed and the solenoid is energized to attract its core. The movement of the core is transmitted through the link 10 and the lever 7, and thence through the shaft of said lever to the lever 5, and thence through the links 6 to the jaws of the brake, forcing said jaws away from the friction-drum' of the brake. At the same time the upward movement of the lever 7 is transmitted through the link 13 to the circuitbreaking arm 14:, which controls the motorcircuits. The mechanism thus started continues in operation until the yoke-nut 19, moving along its threaded shaft, bears against either shoulder 21, whereupon the yoke is turned. The turning of the yoke is transmitted, through the gears 22 23, the crank-arm 24:, the bar 25, the rack 26, and the gear-wheel 27, to the reversing-switch 16. The reversingswitch is thus restored to its normal position, in which all of the circuits are open atits contact-plates. As soon as the circuits are open at the reversing-switch the solenoid and the motor are deenergized and the spring applies the brake to the mechanism. It is noted that while the attraction of the solenoid upon its core increases as the core is drawn into the solenoid this increase of power is counterbalanced by the increase in the tensile force of the spring, which increases as the lever 7 moves upwardly. As the circuit-closing lever and the solenoid are both linked to the lever which operates the brake-jaws, it is impossible to move said lever without moving both the solenoid-core and the eircuit-breaking lever 14. The brake and the circuits, therefore, are mutually interdependent in their operation.

The shaftof the reversing-switch carries a crank-arm 54, connected by a pitman 55 to a bell-crank lever56, which in turn is connected by a link 57 to a radius-lever 58, mounted on the framework. The joint between the lastmentioned link 57 and the radius-lever 58 describes a circular are about the fulcrum of the lever as a center. This joint operates with the tension-spring to force the main lever down in case the ci rcuit-breakin g arm should stick, and it also constitutes a movable safety-stop for preventing an untimely movement of the brake-actuating lever. For this purpose the brake-actuatin g lever is arranged to move across the said circular arc, and its edge is so designed as to barely clear said joint in all its positions during the normal operation of the parts.

While I have described my electric brake in connection with an elevator or hoisting mechanism, it is obviously applicable to other kinds of machiney, and I do not wish to restrict myself to the kind of mechanism described. Obviously, also, my device admits of considerable modification in the construction thereof, and I do not wish to restrict myself to the details of construction hereinbefore described.

What 1 claim is 1. An electric brake comprising a braking mechanism, a lever for operating said mechanism, a solenoid having a core operatively connected to said lever to actuate the same, a circuit-breaking arm operativcly connected to said lever to be moved thereby, and means for automatically retracting said lever to its normal position, said circuit-breaking arm being arranged to control the mo tor-circuits and ear rying contacts in the solenoid-circuit, substantially as described.

2. An electric brake comprising a frictiondrum, brake-jaws, arranged to cooperate with said friction-drum, a lever for operating said jaws, a solenoid having acore operatively connected to said lever to actuate the same, a circuit-breaking arm operativcly connected to said lever to be moved thereby and a spring for automatically retracting said lever to its normal position, said circuit-breaking arm being arranged to control the motor-circuits, and carrying contacts in the solenoid-circuit, substantially as described.

3. An electric brake comprising a braking mechanism, a lever for operating said braking mechanism, a solenoid having a core operatively connected to said lever to release the braking mechanism, a switch arranged to open and close the solenoid and motor circuits and to reverse the armature-circuit, and a circuitbreaking arm in the circuits of the motor operatively connected to said lever to be moved thereby and bearing contacts in the solenoid-circuit.

t. An electric brake comprising a braking mechanism, a lever for operating the same, a solenoid having a core operatively connected to said lever to actuate the same, a switch arranged to open and close the motor and solenoid circuits and reverse the armature-circuit, a circuit-breaking arm in the circuits of the motor and operatively connected to said lever to be moved thereby, and means for automatically retracting said lever to its normal position, and means connected to the reversing-switch for transmitting motion therefrom to said lever to return said lever to its normal position, substantially as described.

5. An electric brake comprising a frictiondrum, brake-jaws arranged to cooperate with said friction-drum, a lever for operatin said jaws, a solenoid having a core operativelyconnected to said lever to actuate the same, a switch arranged to open and close the solenoid, motor-armature and field-circuits and reverse the armature-circuit, a circuit-breaking arm in the circuits of the motorand operatively connected to said lever to be moved thereby, and means for automatically retracting said lever to its normal position, substantially as described. I

6. An electric brake comprising a braking mechanism, a lever for operating the same, a

solenoid having a core operatively connected to said lever to actuate the same, a switch for opening and closing the motor and solenoid circuits and arranged to reverse thearmaturecircuit, a circuit-breaking arm in the circuits of the motor and operatively connected to said lever to be moved thereby and means connected to the shaft of the reversing-switch for transmitting motion therefrom to said lever to return said lever to its normal position, substantially as described.

7. An electric brake comprising a braking mechanism, a lever for operating the same, a solenoid having a core operatively connected to said lever to actuate the same, a switch arranged to open and close the solenoid and motor circuits and reverse the armature-circuit and connected to the power mechanism to be actuated thereby, and means connected to the reversing-switch for transmitting motion therefrom to said lever to return said lever to its normal position, substantially as described.

8.- An electric brake comprising a braking mechanism, a lever for operating the same, a solenoid having a core operatively connected to said lever to actuate the same, a switch arranged to open and close the solenoid, motor armature and field circuits and reverse the armature-circuit, a gear-wheel carried by said switch, a rack engaging said gear-wheel, and means for permitting said reversing-switch to be set by hand and actuated by the power mechanism, a circuit-breaking arm in the circuits of the motor operatively connected to said lever to be moved thereby, substantially as described.

9. An electric brake comprising a braking mechanism, a lever for operating said mechanism, a solenoid having a core operatively connected to said lever to actuate the same, a circuit-breaking arm arranged to control the motor-circuits and operatively connected to said lever to be moved thereby and means for automatically retracting said lever to its normal position, and means connected to the power mechanism for cooperating with said retracting means, substantially as described.

XVALTER LASAR.

Witnesses:

JAMES A. CARR, ZOLA TUCKER. 

